Melly:
For quick & dirty stuff, I don't mind globals a bit. They get to be a problem when the program starts to get too large and complicated. If you ever find yourself using grep to track down usage of a global variable, or when you have a quick reference sheet for your global variables, or when you track down a bug due to reusing a global variable name that you forgot, then you know that your program is past due for some reorganization/refactoring/etc.
I always wonder why quick & dirty programs last longer than the supposedly long-term ones?
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roboticus